Originally Posted by
MWM
I want to add one more thing to this thread, which is an anecdote from my own training. This anecdote suggests that for some trainees, under some conditions, hard conditioning work may actually be a net boon during an NLP rather than an interference. I've gone through an NLP with no conditioning as well as doing one whilst rowing after a long layoff. I have noticed that HIIT, in particular sprints on the rowing machine, have benefited my ability to get through a heavy set of deadlifts. Unlike the other lifts where I have only experienced failure due to straightforward weakness, I have failed the fifth rep of a set of deadlifts several times due to exhaustion - completely 'gassing out' after the fourth rep. I've never 'gassed out' in this way during a set of squats - it's something particular to the deadlift for me.
Whilst I do not think that HIIT makes me any stronger, I have noticed that when I do HIIT on the rowing machine this problem goes away. I still feel fatigued during the pause between the fourth and fifth deadlift rep, but it's much more of the usual muscular fatigue experienced with every other lift, not the systemic, high-lactate 'gassing out' kind of fatigue (which I'm hinting is cardiovascular in nature). As a result I fail far fewer sets and therefore actually make quicker progress than I did without doing HIIT. At the same time, I haven't noticed HIIT slowing or stalling my linear progression, although I should make it clear that I avoid doing it on the same day or the day before my heavy deadlift workouts.